Аннотация:The ethydium bromide (EB) is widely used as a fluorescence probe for the identification of the native DNA. In the study it is first established that the salts of polybases can substitute the intercalated EB molecules because of the formation of interpolyelectrolyte complexes of DNA with the corresponding polycations. The data on luminescence spectra and circular dichroism indicate that the substitution process is controlled mainly by electrostatic interactions. This ability of polycations can be used for the subsequent regeneration of the native DNA.